🔧 Explorer - Timing Chain / “Timing Belt” Replacement

Your Explorer 3.5L EcoBoost does not use a timing belt. It has a timing chain system, which is internal to the engine and designed to last the life of the vehicle under normal conditions. Replacing it is a major engine job, not a typical driveway DIY.

Difficulty Level: Advanced (engine specialist level) | Estimated Time: 10–16 hours

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⚠️ Safety & Precautions

• ⚠️ The timing chain sits behind the front engine cover; access often requires lowering or partially removing the engine. This can be dangerous without proper lifting equipment.
• ⚠️ Incorrect timing chain installation can cause catastrophic engine damage (bent valves, destroyed pistons).
• ⚠️ You’ll work near the starter, alternator, and main power cables—battery must be disconnected before any disassembly.
• ⚠️ Coolant and engine oil must be drained; spills are slippery and harmful to skin and environment.
• ⚠️ The high-pressure fuel system (direct injection) can hold high fuel pressure—improper release can spray fuel.
• ⚠️ This job is not recommended for a first-time DIYer without engine teardown experience.

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🔧 Required Tools

You'll need the following tools for this repair (for reference, if a professional shop or very advanced DIYer does it):

• 🔹Complete metric socket set (8mm–21mm)
• 🔹Metric wrench set (8mm–21mm)
• 🔹1/4", 3/8" and 1/2" drive ratchets
• 🔹Breaker bar 1/2" drive
• 🔹Torque wrench 3/8" drive (5–80 Nm range)
• 🔹Torque wrench 1/2" drive (40–250 Nm range)
• 🔹Torx bit set (T20–T55)
• 🔹E-Torx socket set (E6–E18)
• 🔹Flat blade screwdriver medium
• 🔹Phillips screwdriver medium
• 🔹Plastic trim clip remover
• 🔹Pry bar 12"
• 🔹Harmonic balancer puller (specialty)
• 🔹Engine support bar or engine hoist (specialty)
• 🔹Floor jack (rated 3-ton minimum)
• 🔹Jack stands (rated 3-ton, Qty: 2–4)
• 🔹Drain pan 10+ liters
• 🔹Funnel medium
• 🔹Plastic scraper
• 🔹Razor blade gasket scraper
• 🔹Shop rags
• 🔹Brake cleaner spray
• 🔹Engine timing locking tool set for Ford 3.5L EcoBoost (specialty)
• 🔹Camshaft holding tools for Ford 3.5L EcoBoost (specialty)
• 🔹Crankshaft locking pin for Ford 3.5L (specialty)
• 🔹Fuel line disconnect tool set (specialty)
• 🔹Safety glasses
• 🔹Mechanic gloves

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• 🔹Timing chain kit (primary chain, guides, tensioners, sprockets as required) - Qty: 1
• 🔹Secondary timing chains and tensioners (for both cylinder heads, if not in kit) - Qty: 2
• 🔹Front timing cover gasket set - Qty: 1
• 🔹Valve cover gaskets (left and right) - Qty: 2
• 🔹Crankshaft front seal - Qty: 1
• 🔹Camshaft seals (if applicable) - Qty: 2–4
• 🔹Harmonic balancer bolt (torque-to-yield, single-use) - Qty: 1
• 🔹High-pressure fuel pump gasket/O-ring - Qty: 1
• 🔹Engine oil (5W-30 synthetic, Ford spec) - Qty: 6 quarts
• 🔹Oil filter - Qty: 1
• 🔹Engine coolant (Ford-approved, pre-mix or concentrate) - Qty: 2–3 gallons equivalent
• 🔹RTV engine sealant (for timing cover corners) - Qty: 1 tube
• 🔹Accessory drive belt - Qty: 1
• 🔹Miscellaneous one-time-use bolts (as required by Ford) - Qty: Various

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📋 Before You Begin

• Park the Explorer on level ground, select Park, and set the parking brake.
• Allow the engine to cool fully; timing cover and coolant passages will be very hot after driving.
• Open the hood and remove the engine cover by hand if equipped.
• Disconnect the negative battery cable using a 10mm socket and move it aside so it cannot touch the terminal.
• Raise the front of the vehicle with a floor jack (3-ton) and support securely with jack stands under the proper frame points.
• Have a clean workbench or table ready to lay out parts in order. Keep parts laid out in removal order.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Because this is an advanced engine teardown and you’re a beginner, I’ll outline the main stages so you understand what’s involved. For actual timing chain replacement, a professional should follow the full Ford workshop manual with all torque specs and diagrams.

Step 1: Confirm You Actually Need Timing Chain Service

• Listen for symptoms with the engine running: rattling on cold start, timing-related fault codes (a shop can scan), or severe performance issues.
• If the engine is quiet and there are no timing-related trouble codes, Ford does not recommend routine timing chain replacement on this engine.
• Visit a trusted shop to run diagnostics before deciding on chain replacement. Diagnosis is cheaper than major teardown.

Step 2: Remove Intake and Accessories

• Use a flat blade screwdriver to loosen hose clamps on the intake tube and remove it.
• Unplug sensors and coils by hand; press the locking tabs gently.
• Use a 10mm socket to remove bolts holding the engine cover brackets and other small brackets.
• Remove the accessory drive belt by rotating the tensioner with a 15mm socket and breaker bar, then slipping the belt off the pulleys.

Step 3: Drain Coolant and Engine Oil

• Place a drain pan 10+ liters under the radiator drain or lower hose.
• Use a flat blade screwdriver or hand to open the radiator drain (if equipped) or remove the lower hose clamp and hose.
• Move the drain pan under the oil pan plug; use a 15mm socket to remove the oil drain plug and drain oil.
• Reinstall the drain plug by hand and tighten with a 15mm socket to Torque to 27 Nm (20 ft-lbs).

Step 4: Remove Engine Mount Brackets and Support Engine

• Install an engine support bar over the top of the engine bay or use an engine hoist attached to proper lift points.
• Use a 15mm and 18mm socket to remove engine mount bolts and nuts on the timing cover side as required for access.
• Make sure the engine is safely supported before fully removing any mount bolts.

Step 5: Remove Valve Covers and Front Timing Cover

• Use a 10mm socket to remove valve cover bolts for both cylinder banks, then carefully lift the covers off.
• Use a plastic scraper to remove any RTV or gasket pieces stuck to the head surfaces.
• Remove the crankshaft pulley/harmonic balancer using a harmonic balancer puller after removing the center bolt with a 21mm socket and breaker bar.
• Use the appropriate Torx bits and metric sockets to remove all timing cover bolts; note their locations and lengths.
• Pry gently with a pry bar if needed to break the seal and remove the timing cover.

Step 6: Lock Engine at Top Dead Center (TDC)

• Rotate the crankshaft with a 21mm socket on the crank bolt until cylinder 1 is at TDC as specified by Ford (alignment marks on crank and cams).
• Install the crankshaft locking pin from the timing tool kit into the engine block to lock the crank.
• Install the camshaft holding tools on both banks so the cams cannot rotate.
• Never skip locking tools on a modern engine.

Step 7: Remove Timing Chains, Guides, and Tensioners

• Use the correct Torx or E-Torx sockets to remove bolts from the timing chain guides and tensioners.
• Carefully relieve tension from the chains as you remove the tensioners, then lift off the chains from the sprockets.
• Keep track of which chain and guide came from which bank.

Step 8: Install New Chains, Guides, and Tensioners

• Install new guides and tensioners with the correct Torx or E-Torx sockets, following Ford’s specified sequence.
• Fit the new chains according to the colored links and timing marks on the sprockets.
• Torque all fasteners to Ford’s exact specs (you must reference the service manual; values vary by bolt).
• Release the new tensioners so they apply tension to the chains.

Step 9: Verify Timing and Reassemble Front of Engine

• Double-check that cam and crank timing marks line up with the service manual diagrams.
• Remove the cam and crank locking tools and rotate the engine by hand two full turns with a 21mm socket, then recheck marks.
• Clean the timing cover and engine block surfaces with a razor blade scraper and brake cleaner.
• Apply RTV engine sealant at the specified corners, then install the timing cover and bolts using appropriate metric sockets. Torque to Ford specs.
• Reinstall the harmonic balancer with a new bolt, using a 21mm socket and torque wrench, following the torque + angle procedure in the manual.

Step 10: Reinstall Valve Covers, Mounts, and Accessories

• Install new valve cover gaskets, then reinstall covers with a 10mm socket and torque to spec.
• Reinstall engine mounts and brackets with 15mm and 18mm sockets; torque to Ford specs.
• Reinstall the accessory drive belt by rotating the tensioner with a 15mm socket.
• Reattach intake tubing and reconnect all sensors and coils.

Step 11: Refill Fluids and Final Checks

• Install a new oil filter by hand, then snug it with your hand only.
• Refill the engine with 5W-30 synthetic oil using a funnel.
• Refill the cooling system with the correct coolant mixture using a funnel.
• Reconnect the negative battery terminal with a 10mm socket.

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✅ After Repair

• Start the engine and listen carefully for abnormal noises (rattles, knocking, grinding). Shut off immediately if something sounds wrong.
• Check for warning lights on the dash. Use a scan tool at a shop to clear any codes and verify cam/crank correlation is within spec.
• Inspect for oil or coolant leaks around the timing cover, valve covers, and hoses.
• Let the engine reach operating temperature, then recheck coolant level and top up if needed.
• After a short test drive, check fluid levels and fasteners again.

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💰 DIY vs Shop Cost

Shop Cost: $2,000–$3,500 (parts + labor)

DIY Cost: $500–$1,000 (parts, fluids, sealant)

You Save: $1,500–$2,500 by doing it yourself!

Shop labor rates vary but typically run $100–$150/hour. This repair takes a shop approximately 10–16 hours.

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🎯 Ready to get started?

Given you’re new to wrenching and this job is very complex, I strongly recommend having a professional handle any timing chain replacement on your Explorer, and starting your DIY journey with easier jobs (oil changes, filters, brakes). HowToo makes it easy: same-day/2-day shipping on every part, plus all the tools and specialty tools you need! Check out the parts and tools sections above to add everything to your cart.